Inside casing cutter



pr 1935- w. J. FLURY ET AL I I 1,998,804

7 INSIDE CASING CUTTER Filed Jan. 2, 1954 Inventor:

Patented Apr. 23, 1935 UNITED STATES INSIDE CASING CUTTER William J.

, 5 Claims.

This invention relates to devices for cutting 01f casing within a well, and has as its object to simplify the construction and improve the efficiency of such devices.

Briefly, the invention comprises a set of expansible cutters mounted on a'frame adapted to be lowered into a well casing on the end of a string of driil rod or pipe and a mechanism for expanding the cutters against the casing at a desired point in the well.

The exact construction of the device and its operation will be apparent from the following detailed description, taken in connection with the accompanying drawing, in which Fig. 1 is a vertical view of our cutter as it appears in a well casing, the casing being shown in section;

Figs. 2 and 3, taken together, show an enlarged view of the cutter, portions of Fig. 2 being shown in section;

Fig. 4 is a detailed section in the plane IV-IV of Fig. 2;

Fig. 5 is a detailed section in the plane VV of Fig. 3; and i Fig. 5 is a detailed section in the plane VIVI of Fig. 3. V

Referring to Fig. 1, our cutter comprises a body member 5 adapted to be screwed onto the lower end of a string of drill rod 2,.the body member i having expansible cutters 3 for cutting off a casing. Attached to the lower end of body member l by a shaft 4 is a casing gripping mechanism 5 comprising slips 6 which are adapted to be forced outward against the casing, thus locking the shaft t against downward movement.

Referring now to Figs. 2 and 3, cutters 3 are mounted in recesses l in the sides of body member I, the recesses being substantially the same width as the cutters 13 so that the latter are constrained from tangential movement with respect to body i but are free to move vertically or radially within the recesses 7. Body member 5 is hollow and contains a plunger 3 adapted to move up and down therein. A spring 9 normally forces plunger member 3 downward and the distance downward through which plunger 8 can move is limited by the fact that the lower ends of cutters 3 are pivoted to plunger 8 and the downward motion of the cutters is limited by springs in mounted on member l outside of each cutter 3.

Thus as shown in Fig.2, when plunger 8 is forced down by spring 9 a predetermined distance, the ends of spring if? engage against the outwardly extending faces l l of cutters 3 and prevent further downward motion. This is only one of the Flury, Lewis P. Brandel, and Fran Halfen, Long Beach, Calif. I

7 Application January 2, 1934, Serial No. 704,894

functions of springs H3, their chief function being to force the cutters '3 within the recesses 1 while the device is being lowered through or lifted out of the casing.

The cutters are expanded by forcing plunger 5 member 8 upward within hollow member l, thus raising cutters 3 until they impinge against the outwardly directed faces E2 in the top of the re-. cesses l, thus forcing the upper ends of the cutters 3 outward against the casing, as shown in 10 Fig. 1.

'Mounted in'body member l, below plunger 8, is a plunger 93 havinga ball. I i mounted in the top thereof, adapted under certain conditions to seat in a semispherical seat .l 5 in the lower end of plunger members. Also plunger I3 has a shaft 4 extending below the tubular member I, and the upper end of shaft 4, immediately below plunger i3, is provided with external threads l6 adapted to screw into threads in a bushing H in the lower end of member l. When the threaded portion it of shaft 4 is screwed down into bushing H, as shown in Fig. 2, the plunger i3 is restrained from moving upwardly into engagement with the upper plunger member 8, but by rotating the body member 5 with respect to shaft 4 the former may be screwed downward out of engagement with threads it, thus permitting body member I to slide down over shaft 4 until the ball M in plunger I3 seats in seat l5 in the lower end of. plunger member 3. Thereafter, further downward motion of member 5 forces plung-' er 8 and the cutters 3 upward, thus forcing the upper ends of cutters 3 out into cutting engagement with the casing.

Attached to the lower end of 'shaft i, as by screw threads, is a member 58 having a plurality (three in this instance) of faces IS ,on which slips 5 are slidably mounted. As shown in Fig. i slipsfi are keyed onto faces I9 so that they cannot become detached therefrom, although they may slide freely up and down. Each slip 6 is attached by a link 20 to a collar 2| which fits about a shaft 22 extending downwardly from member i8. Shaft 22 is supplied with a plurality of keyways 23 (three in this instance) in each of which is mounted a slipbar 24. As shown in Fig. 5, each slip-bar 24 is secured adjacent its upper end to the collar 2! as by a countersunk screw 25. Slipbars 24 extend downwardly below collar 25 and have at their lower ends outwardly projecting shoulders 25, as shown in Fig. 3. Surrounding the lower ends of slip-bars 2 is a collar 21. Collar 21 has acircular opening therethrough of such size as to form a loose fit on shaft 22. Since the outer edges of slip-bars 24 are ground to conform with the curvature of shaft 22, collar 21 is free to rotate about shaft 22 and at the same time serves to restrain the slip-bars 24 within the keyways 23.

The shoulders on the lower ends of slipbars 24 engage with the collar 21 to permit its downward motion with respect to the collar ZI and the slips 6.

A plurality of springs 28 are secured at their upper ends to collar 21 at their lower ends to a collar 29 by screws 32. Collar 29 fits loosely on shaft 22 and is provided with a slot 3| adapted to engage a pin 32 projecting radially from the lower end of shaft 22. A head 33 is preferably provided on the lower end of shaft 22 to serve as a guide therefor when the latter is being inserted in a casing. V

The function of all the different elements of our device can best be explained by following through the operation of the device. This operation is carried out as follows:

The slips 6 are retracted to the lower ends of the faces I9 on member l8 by pulling down on the collar 22 and turning it to engage slot 3i with pin 32 on shaft 22. With pin 3| engaged in slot 32, as shown in Fig. 2, the slips 6 are held down so that they cannot ride up on faces I8 and lock with the casing. The member 1 is then turned to the left about shaft 4 until the upper threaded end 56 of shaft 4 is screwed into bushing ll, thus maintaining plunger I3 and ball I4 in the lower end of member l.

Under the conditions outlined, spring 9 forces plunger 8 to its lowermost position with respect to member I and the cutters 3 are retracted into the recesses I. The device is then screwed onto the end of a drill string 2 and is lowered through the casing to the point where it is desired to cut the casing. Lowering of the drill rod 2 is then stopped and the drill rod is turned to the left, thus rotating the body member I, shaft 4, slips 5, shaft 22 and pin 32. However, springs 28, which are in frictional engagement with the casing at all times, tend to remain stationary, thus maintaining the lower collar 29 stationary and permitting the pin 32 tomove out of slot 3|. The drill rod 2 is then lowered further into the easing, and as the springs 28 tend to remain stationary with respect to the casing, the shaft 22 drops through collars 2S and 21 until the collar 2! abuts against collar 2I. Thereafter, further lowering of the drill rod 2 and the elements rigidly attached thereto, forces the member I8 and guides I9 downward while slips 5 are restrained from downward movement by their connecting links 20 and collar 2| resting on top of collar, 21. The slips 6 therefore are forced outwardly until they engage with the casing, as shown in Fig. 1, thus preventing any further downward movement of element I8 and shaft 4.

When all downward movement of shaft 2 ceases, the operatorat the surface of the well knows that the slips 6 are firmly locked in the casing, and he then rotates shaft 2 to the right, at the same time maintaining downward pressure thereon. (This downward pressure may be only that due to the weight of the drill rod 2 within the well so that no surface pressure need be exerted.) Slip 6, being locked in engagement with the casing prevents rotation of shaft 4 so that when the drill rod 2 and member I are rotated to the right, bushing IT and member I rotate about shaft l until the threads I5 are released from the bushing IT. The member I thereupon drops with respect to shaft 4 and plunger I3 until ball I4 seats against the seat I5 provided therefor in the lower end of plunger 8. Plunger 8 and attached cutters 3 are, therefore, restrained from any further downward movement and therefore further downward movement of member I forces the cutters 3 outward because of the tapered faces !2 which contact with the upper ends of cutters 3. As the rotation of drill pipe 2 and body member is continued, the cutters 3 are rotated against the casing until they out completely through it. The operator can tell by the free turning of the drill rod 2 when the cutting operation has been completed. Thereupon, he stops the rotation of the drill pipe 2 and raises it a sufficient distance to bring the upper edge of bushing I"! into engagement with the lower edge of the threaded portion IE on shaft 4. He then rotates the drill pipe 2 and body member Its the left until the a threaded portion of shaft 4 is again screwed entirely into the bushing I I, thus preventing accidental expansion of the cutters 3.

Of course, as soon as body member I was lifted with respect to shaft 4, the spring 9 forced the plunger 8 and the cutters attached thereto downward and at the same time the spring It forced the cutters 3 into the recesses and out of engagement with the casing. As soon as bushing H is screwed onto the threaded end I6 of the shaft 4 as far as it will go, further rotation of drill rod 2 and body member I rotates shaft Shaft 4 can rotate readily at this time because when the body member I was first lifted the shaft 4 and slip guides I9 were also lifted, thus releasing the slips 5 from engagement with the casing.

Rotation of shaft 4 to the left also rotates shaft 22 and as the raising of shaft s also raises shaft 22 the pin 32 rides up into slot 3!. Thereafter, a slight turn of the drill pipe 2 to the right turns shaft 22 with respect to collar 29 and forces pin 32 into slot 3!. This locks collar 29 with respect to shaft 22 and springs 28 prevent the collar 2'! from riding up on shaft 22. The lower edge of collar 21 engages with the shoulders 26 on the keys 24, thus restraining collar 2I from upward movement. Since slips 6 are attached by links 20 to collar 2!, they are prevented from riding up on the guides I9 and the entire device is therefore in the same locked condition it was when originally inserted into the casing. It may, therefore, be withdrawn from the casing or, if desired, it may be lowered still further to cut the casing at a second point lower down.

Since, during the cutting operation, considerable downward force is exerted on the body member I, which is rotating'upon the shaft 4, the latter being maintained stationary with respect to the casing by slips 6, considerable friction results at the contacting portions of plunger member 8 (which turns with body member I) and the upper end of plunger I3 attached to shaft 4. We have found that the use of a ball thrust bearing, as disclosed in Fig. 2, adequately takes care of the heavy thrust developed between members 8 and I3, permitting plunger 8 to turn freely without exerting an objectionable torque on the shaft 4 and the slips 6.

We claim:

1. A device of the type disclosed comprising a hollow body member adapted to be lowered into a well casing on a drill string, a casing-cutting means in said member operable into and out of cutting position, second means positioned entirely within and movable upward with respect to said member for operating said casing-cutting means into cutting position, and third means positioned below said second means and partly within and projecting below said body member for moving said second means with respect to said member, said third means having threads thereon, and threads on said body member adapted to engage with said threads on said third means when the latter is in lowermost position with respect to said member, slip means for securing said third means in a casing, and a bearing member contained within said body members between the upper end of third means and the lower end of said second means.

2. A device of the type disclosed comprising a body member adapted to be lowered into a well casing on a drill string, a casing-cutting means in said member operable into and out of cutting position with said casing, second means rotatable and movable upward with respect to said body member for operating said casing-cutting means into cutting position, locking means releasable by rotation of said body member in one direction with respect to said second means for maintaining said second means in lowermost position with respect to said body member, slips on said second means for engagement with the Well casing, and second locking means releasable by rotation of said second means in a direction opposite to said one direction with respect to the casing for normally maintaining said slips out of locking engagement with said casing.

3. A device of the type disclosed comprising a body member adapted to be lowered into a well casing on a drill rod, a casing-cutting means in said member operable into and out of cutting position, cutter-actuating means movable upward with respect to said body member for operating said casing-cutting means into cutting position, and locking means releasable by relative rotation between said member and said outter-actuating means for securing the latter in lowermost position with respect to said member, slip seats secured to said cutter-actuating means, slips mounted on said seats and movable longitudinally therealong, a shaft extending below said slip seats and attached thereto having keyways therein, keys in said keyways secured together at their upper ends and to said slips, a collar surrounding said shaft and keys for maintaining said keys in their keyways, outwardly extending shoulders on the lower ends of said keys engageable with the lower edge of said collar, means attached to said collar engageable with the casing for resisting motion with respect to the casing, and means attached to said collar releasable by rotation of said shaft with respect to said collar for restraining said slips in lowermost position with respect to said slip-guides.

4. A device of the type disclosed comprising a body member adapted to be lowered into a well casing on a drill string, a casing cutting means movable vertically in said body member and operable into cutting position when moved upwardly with respect to said member, cutter-actuating means pivotally secured to said cutter means and slidably mounted for guided vertical movement within said body member, other means slidably mounted for guided vertical movement within said body member below said cutter-actuating means and projecting below said bodymemvber, anchor means secured to the projecting end of said other means, the lower end of said cutteractuating means and the upper end of said other means each being provided with a central ball seat, and a thrust ball positioned within said body member between saidseats.

5. A device of the type disclosed, comprising a body member adapted tobe lowered into a well casing on a drill string, a casing cutting means in said member operable into and out of cutting position in said casing, second means rotatable and movable upward with respect to said body member for operating said casing-cutting means into cutting position, locking means releasable by rotation of said body member in one direction with respect to said second means for normally maintaining said second means in lowermost position with respect to said body member, slips on said second means for engagement with a well casing, and second locking means releasable by rotation of said second means in a direction opposite to said one direction, with respect to the,

casing, for normally maintaining said slips out of locking engagementwith said casing.

WILLIAM J. FLURY. LEWIS P. BRANDEL. FRANK HALFEN; 

